Salmon Spawning Habitat and Sediments Brad Dunker Municipal Creeks Coordinator Municipality of Anchorage Parks & Recreation

Overview Salmon ecology and behavior during in-migration and spawning What are some impacts of fine sediments on salmon habitat Why sediment control and road crossings are important to salmon Here are some basic questions that I hope we can have an understanding about by the end of the 15 minutes.

Physical Parameters and Embryonic Development “Simple” relationship between physical parameters and steelhead embryonic development. We won’t go over this slide in detail, but just to show you that salmon ecology isn’t always as easy to understand as we would like it to be.

Salmon Ecology Important factors include: Temperature Habitat availability Water velocity In-redd flows

Temperature Embryos typically emerge from the redd

Temperature 13-16° C= ideal temperature for fish to gain weight (in lab) 22-25° C fish stop feeding/spawning +25° C mortality occurs Especially critical for juvenile salmon Salmon embryos have a limited ability to escape from detrimental environmental parameters.

Habitat and Velocity Substrate is important for embryonic and juvenile salmon survival Provides: UV Protection Crushing/Vibration impacts Cover from predation Water Velocity is related to substrate and causes impacts on redds

Redd Making

Redd Attributes

Habitat and Sediment Fine sediments (% of fines) is critical to habitat quality Reduces: Oxygen Supply Metabolic waste removal Ability to stabilize temperature Success of aelvan emergence

In-gravel Flow

Sediment and Embryo Survival

“Good” Sediments? Natural Gravel transport Human Gravel transport Gravels native to that stream system that naturally flows downstream Human Gravel transport Gravels not native to that stream system that are placed by construction activities or restoration projects

Gravel Augmentation Project

Gravel information Handling: Typically handled around 10 times before it is placed in a culvert/streambed Sits in yards after it is processed gaining sediments Must meet native gravel size criteria to be effective

Construction Tips Equipment Storage sites away from stream bank RUBBER TIRES! Environmentally-friendly fluids in equipment Storage sites away from stream bank Gravel quality and specs

Thanks!